SU1641803A1 - Method for preparing 2 2dimethyl-3-oxoalkanals - Google Patents

Abstract

The invention relates to ketoaldehyde, in particular to the preparation of 2,2-dimethyl-3-oxoalkanals of the RCO-C (CHj) 2 - C (0) H, where R is Me, Et, Pr, Zi, which are found use in obtaining drugs. The purpose of the invention is to increase the yield of the target product and simplify the process. The preparation involves the reaction of aliphatic acid anhydride in the form of RCOC1, where R is indicated above, with 2-methyl-propenyloxytrimethylsilane in methylene chloride in the presence of zinc chloride at a molar ratio of 2-methylpropenyloxytrimethylsilane and ZnCl2: 0.0733). The process is preferably carried out at 30-35 ° C. Yield up to 55-80%. The process goes in one stage for 1 hour (against 2 stages and 48 hours by a known method). 1 hp f-ly, 1 tab. 1 (L

Description

The invention relates to p-ketoaldehydes, in particular to an improved process for the preparation of 2,2-dimethyl-3-oxoalkanals of the general formula

RCO-C (CH3) 2-C:

, 0

WH

where R is Me, Et, Pr, Bu, which are used in the preparation of drugs.

The purpose of the invention is to increase the product yield and simplify the process.

Example 1. Synthesis of 2,2-dimethyl-3-oxopentanal.

K 0.1 mol 2-methylpropenyloxytri-5

methyl silane and 1 g of ZnCl2 in 50 ml of methylene chloride, a solution of 0.1 mol of propionyl chloride in 5 ml of methylene chloride is added dropwise. The molar ratio of 2-methylpropenyloxytrimethylsilane and ZnCl2 is 1: 0.0733. After the completion of the dropping, the mixture is stirred for another 45 minutes at 35 ° C, then cooled, 1 ml of dioxane is added, the precipitated zinc salts are filtered off, the solvent is distilled off, and the product is purified by distillation in vacuo. The yield of the product is 57% (7.3 g).

PRI mme R 2. Synthesis of 2,2-dimethyl- .3-oxobutanal,

To O, 1 mole of 2-methylpropenyloxytrimethylsilane and 1 g of ZnCl2 in 50 ml of methylene chloride, pactor 0.1 mole of acetyl chloride is added dropwise in 05 4

(about-.

00

about with

5 ml of methylene chloride. The molar ratio of 2-methylpropenyloxytrimethylsilane and ZnCl is 1: 0.733. The mixture is further processed as in Example 1, Yield 60% (6.8 g).

Example 3. Synthesis of 2,2-dimethyl-3-oxohexanal.

To a solution of 0.1 mol of 2,2-methylpropenyloxytrimethylsilane and 1 g of ZnCl2 in 50 ml of methylene chloride, a solution of 0.1 mol of butyryl chloride in 5 ml of methylene chloride is added dropwise. Next, the mixture is treated as in example 1. Yield 79% (10.3 g).

Example 9. The synthesis of 2,2-dimethyl-3-oxoheptanal is carried out analogously to example 1, except that a mixture of ether 15 and ethyl acetate (1: 1) is used as a solvent. The yield of 26%.

25

EXAMPLE 4 Synthesis of 2,2 dimethyl-3-oxo-heptanal. The physicochemical constants of semi-0.1 mol of 2-methyl-propenyloxy-tritone-keto-aldehydes are methyl silane and 1 g of ZnCl 2 in 50 ml of chlorine in the table.

A solution of 20 ac was added dropwise from methane 1 from examples 1–9, about 0.1 mol of chloride of valery in 50 ml of the process with the declared methylene chloride. Next, the mixture is treated as in example 1. Output 80% (12.5 g),

Example 5: Carrying out the synthesis in Example 1, but in the absence of a ZnCl catalyst, even with two hours of stirring, does not result in a desired product (the reaction does not proceed). Under similar conditions, using Q as a catalyst for TiCl (0.5 ml) results in tarring the product and reducing the yield to 30% in the case of R C. An increase in the content of ZnCl in a mixture of more than 1 g with a ratio of 2-methylpropylenyloxytrimethylsilane and ZnCl 1: 5: 0.0733 causes the catalyst not to dissolve in said mixture. By reducing the ZnCl content to 0.2 g (the indicated ratio is 1: 0.0147), the yield for 2,2-dimethyl-3-oxoheptanal decreases to 68%. With a further decrease in the ZnCl2 content, the reaction is slowed down and the yield decreases.45 R

EXAMPLE 6: Synthesis of 2,2-dimethyl, p., That 3-oxoheptanal is carried out as in Example 1 with a ratio of 2-methylpropenyloxytrimethylsilane and valeric acid chloride 1.5: 1. As a result 0.05 mol is recovered from the distillation steps.

conditions allows to increase the yield of the target product to 55-80% against 42% by a known method and simplify the process by reducing the number of stages from two by a known method to one, and the reaction takes 1 hour (against 43 hours by a known method). ).

Claims (2)

1. A method for producing 2,2-dimethyl-3-oxoalkanals of the general formula .0 Rco - C (SND) 2 -C N H 40 where R is Me, Et, Pr, Bu, which includes interaction with aliphatic acid chloride, which differs in that, in order to increase the yield of the target product and simplify the process, aliphatic acid chloride, 50 where R has the indicated values, is reacted with 2-methylpropenyloxytrimethylsilane in methylene chloride medium in the presence of zinc chloride at a molar ratio of 2-methylpropenyloxytrimethylsilane: ZnCl2 equal to 1: (0,0147-0,0733) 2. The method according to claim 1. About t and h and y 2-methylpropenyloxytrimethylsilane. The yield of the target product. where R has the indicated values, it reacts with 2-methylpropyloxytrimethylsilane in methylene chloride in the presence of zinc chloride at a molar ratio of 2-methylpropenyloxytrimethyl lan: ZnCl2 equal to 1: (0,0147-0.073 2. Method 1) about. u and with the fact that the process lead example /. Iriva / lspne reaction „., on .n 55 with JU-jj j " according to example 1 during the synthesis of 2,2-dimethyl-, Example 7. Carrying out the reaction 3-oxoheptanal at 20 ° C gives the yield (product 63%. Conducting the same synthesis at 45 ° C gives the product yield 55% Example 8. The synthesis of 2,2-dimethyl3-oxoheptanal is carried out similarly to example 1, except that ethyl acetate is used as a solvent. Q Output 30%. Example 9. The synthesis of 2,2-dimethyl-3-oxoheptanal is carried out analogously to example 1, except that a mixture of ether 5 and ethyl acetate (1: 1) is used as a solvent. The yield of 26%. Physico-chemical constants semi As follows from examples 1-9, the implementation of the method for R conditions allow to increase the yield of the target product to 55-80% against 42% by a known method and to simplify the process by reducing the number of stages from two by a known method to one, and the reaction takes 1 hour (against 43 hours by a known method). Invention Formula 1. A method for producing 2,2-dimethyl-3-oxoalkanals of the general formula .0 R - C (SND) 2 -C N H R where R is Me, Et, Pr, Bu, which includes interaction with aliphatic acid chloride, characterized in that, in order to increase the yield of the target product and simplify the process, aliphatic acid chloride, total „Na ,,„ then where R has the indicated values, is reacted with 2-methylpropenyloxytrimethylsilane in methylene chloride medium in the presence of zinc chloride at a molar ratio of 2-methylpropenyloxytrimethylsilane: ZnCl2 equal to 1: (0,0147-0,0733), 2. p.1 ,. About t and h and Continuation of the table. 2,2-Dimethyl-E- 0.9582 1,4254 oxopentanal 2,2-Dnmetk-3- 0.9113 1.448. oxohexaval 2,2-Dimetal-3-, 0.928P 1.4314 oxoheptanal 2,2-Dimethyl-3-: 0.9750 1.42.4 h oxovutanal 1 1.3 2.5 1730; 1710 0.93 1.23 2.4 1735; 1708 1.58 0.33 1.23 2.33 1732; 1709 1.3 2.15 1730; 1710